Reflection

Make an oval shape and fill with black-white gradient. Make sure the black color is full black (C,M,Y,K=100). Drag it on top of the orb and select Screen Blending Mode.

Highlights

Make a tall vertical rectangle and an elongate circle; then Blend it. Duplicate it by Alt-drag to the right.

Make a 3 color gradient path.

Make another highlight using the same Blending technique as in the previous step and select Screen Blending Mode.

3. CD

Use the Gradient tool and fill the CD shapes with white-grey gradient.

Rainbow Gradient

Make some multi-color line strokes as shown below. Make sure the first and last stroke is white because it will be transparent. Use the Blend Tool (W), click on the edge of each stroke starting from left to right.

Mask

Use the CD shape and mask the rainbow gradient by Ctrl+7 or Object > Clipping Mask > Make. Then select Multiply Blending Mode and adjust the Opacity to 26%.

Repeat the previous step to make another rainbow gradient.

4. Music Note Refection

Make 3 oval paths, make sure the outer path is white color(this will make a glow effect). Select all 3 paths, go to Object > Blend > Make (Ctl+Alt+B).

Drag it below the music note and select Multiply Blending Mode , 37% Opacity. Duplicate the refection object by Alt-drag to the right side.

5. Drop Shadow

The last step is to apply a Drop Shadow effect to the CD. Select the outer CD path, go to Effect > Stylize > Drop Shadow and apply the following setting: